Seat reclining device for vehicle

Abstract

Disclosed is a seat reclining device for a vehicle. The seat reclining device comprises an upper toothed bracket fastened to a lower end of a seat back frame; a lower toothed bracket fastened to a rear end of a seat cushion frame; an operating section interposed between the upper and lower toothed brackets, for allowing a seat back to be reclined; and a cover plate for covering the upper and lower toothed brackets and the operating section. The operating section comprises upper teeth internally formed on a circumferential inner surface of a groove which is depressed on the upper toothed bracket; lower teeth externally formed on a circumferential outer surface of a protrusion which projects from the lower toothed bracket toward the upper toothed bracket and is received in the groove of the upper toothed bracket, such that the lower teeth can be meshed with the upper teeth; a pair of cams accommodated in a cam hole which is defined at a center portion of the lower toothed bracket, to rotate the lower teeth of the lower toothed bracket in a desired reclining direction; and a cam spring having both ends which are respectively fitted into spring holes defined in the cams, to bias the cams in opposing radial outward directions.

What is claimed is:  
     
       1. A seat reclining device for a vehicle, arranged at a region where a seat cushion frame and a seat back frame, which constitute a vehicle seat having a seat cushion and a seat back, are connected with each other, to allow an angle of the seat back to be adjusted in forward and rearward directions, the device comprising: 
       an upper toothed bracket fastened to a lower end of the seat back frame;  
       a lower toothed bracket fastened to a rear end of the seat cushion frame;  
       an operating section interposed between the upper and lower toothed brackets, for allowing the seat back to be reclined; and  
       a cover plate for covering the upper and lower toothed brackets and the operating section;  
       wherein the operating section comprises upper teeth internally formed on a circumferential inner surface of a groove which is depressed on the upper toothed bracket; lower teeth externally formed on a circumferential outer surface of a protrusion which projects from the lower toothed bracket toward the upper toothed bracket and is received in the groove of the upper toothed bracket, in a manner such that the lower teeth can be meshed with the upper teeth; a pair of cams accommodated in a cam hole which is defined at a center portion of the lower toothed bracket, to rotate the lower teeth of the lower toothed bracket in a desired reclining direction; and a cam spring having both ends which are respectively fitted into spring holes defined in the cams, to bias the cams in opposing radial outward directions; and  
       wherein each cam has a shaft hole through which an operating shaft is fitted; a boss which is formed around the shaft hole on a surface of the cam; an operating cam part which is formed on a circumferential outer surface of the cam to extend through a first predetermined angle and is brought into contact with a circumferential inner surface of the lower toothed bracket, defining the cam hole, the operating cam part having an eccentric center which is deviated from a center of the cam hole, to serve as a wedge; a concentric part which is formed on a surface of the operating cam part, farthest from the boss, to extend through a second predetermined angle less than the first predetermined angle, and has a stepped portion in a manner such that concentric parts of the pair of cams can be brought into contact with each other; and a key groove which is defined to be communicated with the shaft hole in a manner such that a key integrally formed on the operating shaft can be received in the key groove to operate the cam toward a recline permitting position.  
     
     
       2. The seat reclining device as set forth in  claim 1 , wherein the lower teeth has the number of teeth which is less than that of the upper teeth, in a manner such that a position of the upper toothed bracket can be changed by rotation of the lower tooth bracket.